INFRARED STUDY OF HYDROGEN ADSORBED ON C(2 X 8) AND (2 X 6) GAAS(100)

The infrared spectra of adsorbed hydrogen and deuterium on c(2x8) and (2x6) GaAs(100) contain a series of bands from 2200 to 1200 (1600 to 1 000) cm-1 that are due to arsenic hydrides, terminal gallium hydrides, and bridging gallium hydrides (and deuterides). The latter is the fir st known example of bridge-bonded hydrogen on a semiconductor surface. Polarized spectra reveal that the AsH and GaH bonds orient along the [110BAR] and [110] axis, respectively. These results are consistent wi th a GaAs surface structure composed of As and Ga dimers with dimer bo nds in the [110BAR] and [110] directions.